Railway traffic controlling apparatus



July 12, 1938. a c. E. STAPLES 2,123,753

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed April 16, 1937 2Sheets-Sheet 1 m INVENTOR HIS ATTORNEY July 12, 1938. c. E. STAPLES;2,123,753

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed April 16, 1937 '2Sheets-Sheet 2 INVENTOR Crawford taples BY 6 2 i HIS ATTORNEY PatentedJuly 12, 1938 RAILWAY TRAFFIC CONTROLLING APPARATUS Crawford E. Staples,Wilkinsburg, Pa, assignor to The Union Switch & Signal Company,Swissvale, Pa, a corporation of Pennsylvania Application April 16, 1937,Serial N0. 137,293

13 Claims.

My invention relates to railway traffic controlling apparatus, and moreparticularly to apparatus for controlling wayside and/or cab signals bymeans of coded trackway energy. Specifically, my invention relates tothe electric tuning of a signal control-relay circuit which circuit issupplied with energy of either one or two frequencies to correspond tothe rate ofoperation of a code following relay.

The apparatus shown in this application is an improvement on theapparatus shown and claimed in an application of Frank H. Nicholson andLeslie R. Allison, Serial No. 210,744, filed May 28, 1938, for Railwaytraffic controlling apparatus.

One object of my invention is to provide means for automaticallyaltering the tuning of the circuit to correspond to the frequency of theenergy flowing therein and for indicating which frequency is present.

I shall describe several forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view illustratingone form of wayside apparatus embodying my invention. Fig. 2 is adiagrammatic view showing a portion of train carried apparatus toillustrate how train carried signal control relays, similar to thewayside control relay shown in Fig. 1, can be utilized to control a cabsignal. Fig. 3 is a diagrammatic view illustrating another form of traincarried apparatus embodying my invention. Fig. 4 is-a diagrammatic viewillustrating a modification of a portion of the apparatus shown in Fig.3 and also embodying my invention.

Similar reference characters refer to similar parts in each of theviews.

Referring to Fig. l, the reference characters I and 2 designate therails of a stretch of railway track along which traific normally movesin the direction indicated by the arrow. The rails l and 2 are dividedby insulated joints 3 into a plurality of track sections of whichsection 45 4-5 is a representative section. Each track section isprovided with a code following track relay designated by the referencecharacter TR with a prefix to correspond to the location. Each tracksection is also provided with a wayside signal designated by thereference character S with a prefix to correspond to the location andhere shown as a color light signal. Each section is provide-d with ahome signal control relay, a distant signal control relay, a distantsignal control repeating relay, and an auxiliary relay of the flashertype designated by the reference characters H, D, DP, and P,respectively, each with a prefix to correspond to the location.

tion of contacts 8 and 9 is, as will bee more in detail hereinafter, at'75, 120,

xplained or 180 times per minute in accordance with trafiic conditionsin advance. When the front contact 8 is closed, energy will flow frompoint of terminal B of a convenient source of current through wire l9and left-hand portion of primary winding ll of transformer 4M toterminal C of the same source of energy. The front point of c ontact 9of relay 4TB being closed simultaneously with the front point of contact8, energy will flow from one terminal of secondary winding I2 oftransformer 4M through wire l3, relay 4H, wire I4, front point ofcontact 9 of relay 4TB, and wire IE to the other terminal of theleft-hand portion of secondary winding l2. When the back point ofcontact 8 of relay 4TB. is closed, terminal B will be connected withwire 16 soergy will flow in the opposite direction that enthrough theright-hand portion of primary winding. ll

of transformer 4M and, since the back contact 9 of relay 4TB. is alsoclosed will flow from the right-hand portion ondary winding l2 oftransformer 4M wire 13, relay 4H, wire I4, backpoint point of energy ofsecthrough of. contact 9, and wire I! to the other terminal of theright-hand portion of secondary winding !2. In other words, regardlessof the particular code which relay STR is following, the winding ofrelay 4H will always be energized in one direction so that that relaywill become picked up-v on any of the codes.

Relay 4D receives energy from a rectifier 18 which is connected to asecondary winding l9 of transformer 4N. Primary winding 29 oftransformer 4N is supplied with energy by means of a circuit whichincludes wires l9 and l 6 which circuit may be tuned to pass energy ofeither one of two frequencies to correspond to the 180 codes. includedin the circuit, the tuning will 120 and That is, when condenser 2| onlyis be such that only energy corresponding to the 180 code will be passedto primary winding 20 whereas,

when condenser 22 is connected in multiple with condenser 2|, of afrequency corresponding to the l the circuit will pass only energy 20code? The tuning of the circuit for primary winding 20 is controlled bya contact 24 of the auxiliary relay 4P, that is, when contact 24 is inits normal position as shown in the drawings, condenser 22 isdisconnected from the circuit so that energy of a frequencycorresponding to the 180 code will be passed freely to primary winding20 whereas, when contact 24 is in its reverse position so that contact2425 is closed, condenser 22 is connected in multiple with condenser 2|to alter the tuning of the circuit to pass only energy of a frequency tocorrespond to the 120 code.

Relay 4? is provided with a winding 26 and a winding 21 Wound inopposition and is controlled by the relays 4H and 4D. In other words,upon a change from 120 code to 180 code or vice versa, the relay 4D willbecome deenergized to establish a circuit for relay 4P which circuitincludes front point of contact 28 of relay 4H and back point of contact29 of relay 4D. When the circuit for relay 4P is closed, the windings 26and 2! will be alternately energized over contact 30 of relay 4P so thatcontacts 24, 30, 3|, and 32 of relay 4? will alternate between theirnormal and reverse positions. When contact 24 is in the proper positionto bring correspondence between the tuning of the circuit for primarywinding 20 of transformer 4N and the rate of operation of code followingrelay 4TB, relay 4D will, of course, become energized to disconnectenergy from relay 4P. The latter relay is of the type which will remainin its last operated position so that the tuning of the circuit for theprimary winding 20 of transformer 4N will be maintained until anotherchange occurs in the operation of code following relays 4TB.

Relay 4DP is provided with a slow releasing characteristic and iscontrolled by a circuit which includes front point of contact 28 ofrelay 4H and front point of contact 29 of relay 4D. Relay 4DP will,therefore, become energized or deenergized in accordance with theenergization or deenergization of relay 4D since relay 4H remains pickedup on any of the codes.

For supplying energy to the rails, each section is provided with a trackbattery designated by the reference character TB with a prefixcorresponding to the location. For periodically interrupting the supplyof track circuit energy, each section is provided with a codetransmitting relay designated by the reference character CTM with aprefix to correspond to the location. A constantly operating codegenerating relay designated by the reference character CT with a prefixcorresponding to the location is provided with contacts 15, I20, and I80which contacts operate respectively at 75, 120, and 180 times perminute. As will be explained more in detail hereinafter, the relays CTMare connected with contacts 15, I20, or l8i! of the associated relays CTto cause operation of the relays CTM at a corresponding rate inaccordance with the condi tion of the corresponding relays H and DP.

Having described certain elements of the systern individually, I shallnow describe the operation of the system as a whole. When at least threeblocks in advance of location 5 are unoccupied, track relay 5TB. will befollowing 180 code as a result of which relays 5H, 5D, and EDP will allbe energized.

At this time the relay 5H is supplied with current in one directionthrough the transformer 5M, and as a result the contact operated therebygnd corresponding to the contact 28 associated with the relay 41-1 isheld in engagement with its front contact, thereby completing a circuitthrough which current may be supplied to the winding of the relay 5DP orto the windings of the relay 5P.

As the track relay 5TB. is supplying alternating current of the 180 codeto the circuit identified by the numerals I and I 6 at location 4,current at this code frequency will be supplied to the primary windingof the transformer N. If on the initial supply of current of the 180code frequency to the circuit of the primary winding of the transformer5N this circuit is not tuned to permit flow of current of this codefrequency, no current will flow through the primary winding of thetransformer, and no current will be supplied by the secondary of thetransformer to the winding of the relay 5D. As a result the movablecontact of the relay 5D will remain in engagement with its back contact,thereby establishing a circuit through which current may be supplied tothe windings of the relay 5?. The circuits through the windings of therelay 5P are controlled by the movable contact 3i! of the relay 5?,while the contact 24 of this relay controls the tuning of the circuitthrough the primary of the transformer 5N.

At times when the circuit through the primary of transformer 5N is nottuned to permit flow of current of the 180 code frequency, the movablecontacts 30 and 24 of the relay 5P are in their reverse positions,instead of their normal positions as shown in Fig. 1 of the drawings. Onthe supply of current to the circuit leading to the windings of therelay 5P at a time when the contact 30 is in its reverse position, acircuit is established through the lower winding of the relay. Uponenergization of this winding of the relay, the movable contacts 24 and39 are moved to their normal positions as shown in Fig. 1 of thedrawings. On movement of the contact 24 to its normal position, thecondenser for tuning the circuit of the primary of the transformer 5N to120 code frequency is removed from the circuit, leaving only thecondenser for tuning the circuit for 180 code in the circuit of thetransformer primary.

As soon as the circuit of the transformer primary is tuned for the 180code frequency, current flows through the transformer primary windingand induces a current in the secondary which is supplied through theassociated rectifier to the winding of the relay 5D, thereby causing themovable contact of the relay 5D to be moved out of engagement with itsback contact and into engagement with its front contact, andinterrupting the circuit to the windings of the relay 5P. On theinterruption of the supply of current to the winding of the relay 5P,the contacts 30 and 24 remain in the positions to which they have beenmoved.

The relay 5P is comparatively slow acting so that when the contact 24 ismoved to a position to tune the circuit of the transformer 5N to theproper code frequency, it will remain in that position long enough forthe winding of the relay 5D to be energized to thereby operate itsmovable contact and interrupt the circuit to the windings of the relay5P.

It will be seen therefore that on the supply of current of the 180 codefrequency, the relay 5P will be operated to tune the circuit of theprimary of the transformer 5N to permit flow of current of the 180 codefrequency if the circuit is not already tuned to that frequency.

On movement of the movable contact of the relay ED into its engagementwith its front con.- tact, a circuit is established through the wind ingof the relay EDP so that the movable contact 35 is held in engagementwith its front contact, while the movable contact 36 engages its frontcontact when energy is supplied to the winding of the relay EH.

Relay ECTM will be operating on 180 code by virtue of a circuit whichpasses over a path from terminal B through contact I of relay ECT, frontpoint of contact 35 of relay EDP, front point of contact 36 of relay 5H,and relay ECTM to terminal C. The supply of energy from track battery5TB to the rails of section 4.E will there: fore be periodicallyinterrupted by contact Elof relay ECTM at the rate of 180 times-perminute.

When relay ETR is following 180 code, section 4-5 will be supplied with180 code, as described above, and signal ES is controlled by relays 5H,EDP, and EP will provide an indication corresponding to clear traificconditions in three advance blocks. The manner in which signal ES iscontrolled by the relays EH, EDP, and EP will be obvious from thedrawings and it is believed to be unnecessary to trace the signalcontrol circuits in detail.

If the current supplied to the block in advance of station E is changedfrom 180 code to code at a time when the equipment at station 5 isconditioned to respond to current of the code frequency, the codefollowing relay ETR will operate to supply alternating current to thecircuit of the primary winding of the transformer EN at the 120 codefrequency while the relay EH will be supplied with unidirectionalcurrent,

As the circuit of the primary winding of the transformer EN is tuned topermit only current of the 180 code frequency to flow therein, currentof the 120 code frequency cannot flow in this circuit, and accordingly,current will not be supplied to the winding of the relay ED. The movablecontact of the relay ED therefore will engage its back contact andestablish a circuit to the windings of the relay EP. Current thereuponwill flow through this circuit and the polar contact 39 to the upperwinding of relay 5P. Upon energization of this winding, the contacts 39and 24 are moved from their normal positions, as shown in Fig. l of thedrawings, to their reverse positions. On this movement of the contact{24, the condenser corresponding to that identified by the referencenumeral 22 at station 4 is con nected in multiple with the othercondenser with the result that the circuit of the primary winding of thetransformer EN will be tuned to permit flow of current of the 120 codefrequency.

The winding of the relay .ED will thereupon .be energized, and will moveits movable contact out of engagement with its back contact, therebyinterrupting the circuit to the winding of the relay EP, and intoengagement with its front con.- tact, thereby supplying current to thewinding of the relay EDP to cause the movable contact 35 to be held inengagement with its front contact to establish a circuit from the 180contact of the code generating relay EST to the code transmitting relayECTM.

If two blocks in advance of location E are unoccupied, and the thirdblock in advance is .00- cupied, relay ETR will be following 120 codewith the result that relays 5H, ED, and EDP willall be energized, asexplained above. Relay ECT will again be operating on 180 code over thecircuit previously described so that the rails -.of section i5 willcontinue to be supplied with 180 .code.

The cpntacts of relay EP will, however, be in their reverse positionbecause, during the change from 180 code to 120 code, relay ED will havebecome momentarily deenergized to initiate the operation of relay EP. Aspreviously described, the reversal of contact 24 of relay 5P to closecontact 24-25 will change the tuning of the circuit for transformer,ENso that relay ED will become energized when relay ETR is operatingupon 120 code. The reversalof contacts Bland 32 of relay EP willestablish circuits so that signal ES will display an indicationcorresponding to two clear blocks in advance.

If-the block in advance of location 5 is unoccupied and the second blockin advance is occupied, a

relay ETR will be following l5 code with the result that relay EH willbe energized, but relay ED will not be energized because, as previouslystated, the circuit of the primary 20 of the transformer 4N is tuned topass energy only of the 126 and 180 code frequencies, and consequentlyrelay EDP will be deenergized. Relay ECTM will now be operating on 120code by virtue of a circuit which passes over a'path from terminal Bthrough contact I20 of relay ECT, back point of contact 35 of relay EDP,front point of contact 36 of relay EH, and relay ECTM to terminal C. Therails of section 45 will therefore be supplied with 120 code and signalES, .due to the deenergization of relay EDP, will display an indicationcorresponding to one clear block in advance.

If the block in advance of location E is occupied, relay ETR will bedeenergized with the result that relays EH, ED, and EDP will also bedeenergized. Under this condition, relay ECTM will be operating on '75code over a circuit which includes contact '55 of relay ECT, back pointof contact 36 of relay EH, and relay ECTM to terminal C. The rails ofsection l-5 will therefore be supplied with '75 code and signal ES willbe displaying a stop indication to indicate that the block immediatelyin advance of location 5 is occupied.

The relays H are provided with a slow release characteristic so thatthese relays will not become released during changes in the direction ofenergization of the associated transformer M. The relays D? are providedwith aslow release characteristic so that these relays will not becomereleased when the associated relay D becomes released during periods ofchange in the frequency of the energy supplied to the associatedtransformer N. It will be apparent, therefore, that since the relays Hand DP control the signal operating circuits and the supply of energy tothe f} section next in rear, the slow releasing characteristic of theserelays avoids signal flashing and disturbances in the energization ofthe track section to the rear.

Referring now to Fig. 2, the reference character MR designates a traincarried code following relay which receives energy from the rails I and2 inductively through coils M and 5! and amplifier 42. The contacts 43and 44 of relay M-R follow code in a manner similar to that describedfor the 1 contacts 8 and 9 of the track relays TR. It will be apparent,therefore, that, if contacts 43 and 44 nal similar to signal S.

Referring next to Fig. 3, the reference character 45 designates-asecondary winding of transformer M which is connected to winding 2'6 ofauxiliary relay P. Winding 21 of auxiliary relay P is connected inseries with the turned circuits for transformer N. When the tuning ofthe circuit for transformer N corresponds to the frequency of thecurrent flowing therein, energy will flow in winding 21 in a directionopposite to that which flows in winding 26 so that relay P will remainstationary. When, however, a change occurs in the frequency of theenergy supplied to transformer N, energy will be prevented from flowingin winding 2'! but alternating current energy will be flowing in winding26 so that contact 24 will alternate between its normal and reversepositions in response to the alternating current supplied to transformerM by code following relay MR. If the frequency of the energy supplied totransformer N corresponds to 180 code, contact 24 will assume and willremain in the position shown in the drawings because winding 2'! will besupplied with current equal and opposite to that supplied to winding 26.On the other hand, if the frequency of the energy supplied totransformer N corresponds to code, contact 24 will assume and willremain in its reverse position because condenser 22 will then beconnected in multiple with condenser 2| to energize winding 21 in adirection opposite to Winding 26.

In operation, on the supply of energy to the code following relay MR ofthe system shown in Fig. 3 at the 75 code, alternating current issupplied thereby to the primary of the transformer C, whileunidirectional current is supplied to the winding of the relay H. Onthis supply of alternating current to the transformer C, current isinduced in the secondary winding 45 and is supplied therefrom to thewinding 26 of the relay P.

On the supply of alternating current of the 15 code by the relay MR,current does not flow in appreciable quantity through the primarywinding of the transformer N, since as pointed out above, the circuit ofthe transformer primary winding is tuned to permit flow of current ofthe 120 and codes only. Accordingly on the supply of current of the '75code, no current is supplied to the winding of the relay D, while thewinding 21 of the relay P remains deenergized. At this time, aspreviously stated, the winding 26 is supplied with alternating currentat the 75 code from the secondary 45, with the result that the polarcontact 24 and the other polar contacts will oscillate between theirreverse and normal positions. This is without consequence, however,since at this time the relay D is deenergized and its movable contactsengage their back contacts.

On the subsequent supply of current to the relay MR at the 120 codefrequency, this relay operates to supply alternating current at thisfrequency to the primary winding of the transformer M, and to supplyunidirectional current to the relay H. On the supply of current to theprimary of the transformer M, current is induced in the secondary 45 andissupplied therefrom to the winding 26 to cause the polar contacts ofthe relay P to oscillate. The contact 24 accordingly is moved into andout of engagement with its reverse polar contact to thereby complete andinterrupt a circuit to connect the condenser 2| in multiple with thecondenser 22.

When the condenser 2| is connected in multiple with the condenser 22,the circuit is tuned to permit flow of current of the 120 codefrequency. Accordingly when current of the 120 code frequency issupplied by the relay MR, the contact 24 of the relay P will beoscillated until it engages its reverse contact, in which it connectsthe condenser 2| in multiple with the condenser 22, thereby tuning thecircuit of the primary winding of the transformer N for current of the120 code frequency with the result that current is caused to flowthrough the winding 21 of the relay P. On energization of the winding21, which opposes the winding 26, further movement of the contact 24 isprevented, and this contact remains in engagement with its reversecontact, and so also do the other contacts of the relay P.

On the flow of current in the primary winding of the transformer Nsubsequent to the tuning of the circuit through this winding for 120code frequency, current is supplied from the transformer secondary tothe relay D, and its movable contacts are moved into engagement withtheir front contacts as shown in Fig. 3 of the drawings.

On the supply of current of the 180 code frequency to the relay MR,current at this frequency is supplied to the transformer M, whileunidirectional current is supplied to the relay H. In addition, currentis induced in the secondary 45 and is supplied therefrom to the winding26 of the relay P with the result that the movable contacts of the relayP will oscillate between their normal and reverse positions.

Assuming that on the initial supply of current of the 180 code frequencyby the relay MR, that the circuit of the primary of the transformer N istuned for the 120 code frequency, current of the 180 code frequency willnot initially flow through the primary of the transformer N and throughthe winding 21 of the relay P. As soon as the contact 24 is moved fromits reverse position to its normal position the condenser 2| isdisconnected from the circuit of the primary of the transformer N,thereby tuning this circuit for the 180 code frequency. When the circuitis tuned for 180 code frequency, current of this frequency flows throughthe winding 21 and holds the contact 24 in the normal position tomaintain the circuit tuned for 180 code frequency, while current flowsthrough the primary of the transformer N with the result that current issupplied to the winding of the relay D.

With the form of apparatus shown in Fig. 3 the slow releasing relay DPis not required because relay D will not become released during thechange from one code to another.

Referring now to Fig. 4, the reference character 46 designates asecondary winding of transformer N which is connected in series with butin opposition to secondary winding 45 of transformer M. Relay P isconnected to a rectifier 41 which is in turn connected to secondarywindings 45 and 46 in series. When the tuning of the circuit fortransformer N corresponds to the frequency of the energy flowingtherein, the current induced in secondary winding 46 will be equal andopposite to that induced in secondary winding 45 so that no current willflow to relay P through rectifier 41. When the frequency of the energysupplied to transformer N is out of correspondence with the tuning ofthe supply circuit for this transformer, relay P will become energizedby secondary winding 45 of transformer M because no opposing currentwill be flowing in secondary winding 46 of transformer N. Under thiscondition, contact 24 of relay P will assume a position to bring aboutcorrespondence between the tuning of the circuit for transformer N andthe frequency of the energy flowing therein. That is, with contact 24 inits normal position as shown in the drawings, condenser 2| alone willbeconnected in the circuit for transformer N whereas, when contact '24 isin its reverse position so that contact 24-25 is closed, condensers 2Iand 22 will be connected in parallelto pass energy of the frequencycorresponding to I20 code.

In operation of the system shown in Fig. 4, on the supply of current ofthe I5 code frequency to the relay MR, this relay supplies alternatingcurrent of this frequency to the primary of transformer M, whileunidirectional current is supplied to the relay H. On the supply ofalternating current to the primary of transformer M, current is inducedin the secondary 45, and is supplied therefrom through the rectifier 41to the windings of the relay P. On this supply of alternating current tothe windings of the relay 'P, the movable contacts of this relay areoscillated between their normal and reverse positions.

On the supply of current of the I5 code frequency, current does not flowthrough the primary of the transformer N since this circuit can only betuned to permit the flow of current of the I20 or I80 code frequencies.Accordingly current will not be supplied to the winding of the relay Dand its movable contacts will remain in engagement with their backcontacts.

On the supply of current of the I20 code frequency to the relay MR, itsupplies alternating current of this frequency to the transformer M,while current of this frequency is supplied by the secondary winding 45to the relay P through the rectifier 41 with the result that the movablecontacts of the relay P oscillate between their normal and reversepositions.

As soon as the movable contacts of the relay P are moved to theirreverse positions, the condenser 22 is connected in multiple with thecondenser 2I, thereby tuning the circuit of the primary of thetransformer N for the I20 code frequency. Current of the I20 codefrequency therefore will flow through the transformer primary and willinduce current in the secondary from which current is supplied to thewinding of the relay D.

When current of the I20 code frequencyflows through the primary oftransformer N, current is induced in the secondary winding 46. Thiscurrent opposes and neutralizes the current induced in the secondary 45of transformer M with the result that no current will besupplied-through the rectifier 41 to the relay P.

When the circuit of the transformer N is tuned to permit flow of currentof the I20 code frequency, the supply of current to the relay P is cutoff and the contact 24, therefore, will remain in the position toconnect the condenser 22 in multiple with the condenser 2I and maintainthe circuit of the transformer tuned to pass energy of the I20 codefrequency.

When current of the I80 code frequency is supplied to the relay MR, itsupplies alternating current at that frequency to the primary of thetransformer M, and current at this code frequency is induced in thesecondary winding 45. Assuming that the circuit of the primary windingof the transformer N is tuned to pass energy of the I20 code frequency,then on the supply of current at the I80 code frequency, current willnot fiow through the transformer N. Accordingly no opposing current willbe present in the secondary 46 and current induced in the secondary 45will be supplied through the rectifier 41 to the relay P. On the supplyof current to the relay-P, the contacts thereof are oscillated betweentheir reverse and normal positions. As soon as the contact 24 is movedto itsnormal position, the condenser -22 is removed from the circuit ofthe transformer N, thereby tuning that circuit to pass energy of the I80code frequency.

When thiscircuit is tuned to pass energy of the I80 code frequency,current of this frequency will flow through the primary of thetransformer N, thereby inducing current in the secondary 46 whichopposes and neutralizes the current supplied by the secondary 45. Nocurrent will be supplied to the relay P, therefore, and the contact 24will remain in its normal position and maintain the circuit of theprimary winding of the transformer tuned to pass energy of the I80 codefrequency.

In addition, on the flow of current of the I80 code frequency in theprimary of the transformer N, current is induced in the secondary fromwhich current is' supplied to the winding of the relay D.

Although the apparatus shown in Figs. 3 and 4 has been described asbeing of the train carried type for controlling acab signal, it will beapparent thatsimilar trackway apparatus can also be used to controlwayside signals.

Although I have herein shown and described only three forms of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a coded signaling system, a code following relay at times suppliedwith energy periodically interrupted at one rate and at other'timessupplied with energy periodically interrupted at another rate, a circuitcapable of being tuned to a first condition to pass energy of a firstfrequency or to a second condition to pass energy of a second frequency,means governed by said code following relay for supplying said circuitwith energy of one or the other of said two frequencies in accordancewith the rate of operation of said code following relay, a control relayreceiving energy from said circuit, and means governed by currentsupplied to said circuit for alternately adjusting the tuning of saidcircuit from said one to said other condition at predetermined timeintervals until the frequency for which said circuit is tunedcorresponds to the rate of operation of said code following relay.

2. In a coded-signaling system, a code following relay at times suppliedwith energy periodically interrupted at one rate and at other timessupplied with energy periodically interrupted at another rate, a circuitcapable of being tuned to a first condition to pass energy of a firstfrequency or .to a second condition to pass energy of a secondfrequency, means governed by said code following relay for supplyingsaid circuit with energy of one or the other of said two frequencies inaccordance with the rate of operation of said code following relay, acontrol relay receiving energy from said circuit, another relay whichalternates between one condition and another condition when energizedand which remains in the condition to which lastoperated whendeenergized, means for energizing or deenergizing said other relayaccording as said control relay is deenergized or energizedrespectively, and means effective to tune said circuit to said first orsaid second condition according as said other relay is in said one orsaid other condition respectively.

3. In combination, a section of railway track, means for supplying therails of said section with coded energy of one rate or another rate inaccordance with traffic conditions in advance, a code following relayreceiving energy from the rails of said section, a circuit capable ofbeing tuned to pass energy of one frequency or to pass energy of anotherfrequency, means governed by said code following relay for supplyingsaid circuit with energy of said one frequency or said other frequencydepending upon the rate of operation of the code following relay, acontrol relay receiving energy from said circuit, an auxiliary relaywhich alternates between one condition and another condition whenenergized and which remains in the condition to which last operated whendeenergized, means for energizing or deenergizing said auxiliary relayaccording as said control relay is deenergized or energizedrespectively, means for tuning said circuit in accordance with thecondition of said auxiliary relay, and a traffic governing devicecontrolled by said auxiliary relay and by said control relay.

4. In combination, a section of railway track, means for supplying therails of said section with coded energy of one rate or another rate inaccordance with traffic conditions in advance, a code following relayreceiving energy from the rails of said section, a circuit capable ofbeing tuned to pass energy of one frequency or to pass energy of anotherfrequency, means governed by said code following relay for supplyingsaid circuit with energy of said one frequency or said other frequencydepending upon the rate of operation of the code following relay, acontrol relay receiving energy from said circuit, an auxiliary relay,means effective when the frequency of the energy supplied to saidcircuit is changed to cause said auxiliary relay to assume one conditionor another condition to establish correspondence between the tuning ofsaid circuit and the frequency of energy supplied thereto, and a trafiicgoverning device controlled by said auxiliary relay and by said controlrelay.

5. In combination, a section of railway track, means for supplying therails of said section with coded energy of one rate or another rate inaccordance with traffic conditions in advance, a code following relayreceiving energy from the rails of said section, a circuit capable ofbeing tuned to pass energy of one frequency or to pass energy of anotherfrequency, means governed by said code following relay for supplyingsaid circuit with energy of said one frequency or said other frequencydepending upon the rate of operation of said code following relay, acontrol relay receiving energy from said circuit, means including anauxiliary relay governed by flow of current in said circuit forautomatically tuning said circuit to correspond to the frequency of theenergy supplied thereto, contacts governed by said auxiliary relay forindicating which of said frequencies is present, and a signal for saidsection governed by said contacts and said control relay.

6. In combination, a section of railway track, means for supplying therails of said section with coded energy of a first, second, or thirdrate respectively in accordance with traffic conditions in advance, acode following relay receiving energy from the rails of said section, acircuit capable of being tuned to pass energy of one frequency or topass energy of another frequency, means governed by said code followingrelay for supplying said circuit with energy of said one frequency orsaid other frequency according as said code following relay is suppliedwith coded energy of said second or said third rates respectively, meansincluding an auxiliary relay for automatically tuning said circuit tocorrespond to the frequency of the energy supplied thereto and forindicating the frequency present, a first control relay which becomesenergized when said code following relay is operating at any of saidrates, a second control relay receiving energy from said circuit, and atraffic governing device for said section governed by said first andsecond control relays as well as by said auxiliary relay.

'7. In combination, a code following relay, means for selectivelyoperating said code following relay at one rate or at another rate, acircuit capable of being tuned to pass energy of one frequency oranother frequency, means including a contact of said code followingrelay for supplying said circuit with energy of said one frequency orsaid other frequency to correspond to the rate of operation of said codefollowing relay, a control relay receiving energy from said circuit, anauxiliary relay having two windings, means effective when said controlrelay is released to energize said two windings al ternately to cause acontact of said auxiliary relay to assume one condition or anothercondition respectively, means including a contact of said auxiliaryrelay for automatically tuning said circuit to correspond to thefrequency of the energy present therein, a slow releasing repeatingrelay governed by said control relay, and a signal governed by saidrepeating relay and a contact of said auxiliary relay.

8. In combination, a code following relay, means for selectivelyoperating said code following relay at one rate or at another rate, acircuit capable of being tuned to pass energy of one frequency oranother frequency, means including a contact of said code followingrelay for supplying said circuit with alternating current energy of saidone frequency or said other frequency to correspond to the rate ofoperation of said code following relay, an auxiliary relay having twowindings wound in opposition, means for energizing one of said windingsby energy of either frequency supplied by said code following relay tocause a contact of said auxiliary relay to alternate between twodifferent positions, means for altering the tuning of said circuit inaccordance with the position of said contact, said other winding beingincluded in said circuit thereby preventing the operation of saidauxiliary relay when the tuning of said circuit corresponds to thefrequency of the energy flowing therein, and a control relay receivingenergy from said circuit.

9. In combination, a code following relay,

.rneans for selectively operating said code following relay at one rateor at another rate, a circuit capable of being tuned to pass energy ofone frequency or another frequency, means including a contact of saidcode following relay for supplying said circuit with energy of said onefrequency or said other frequency to correspond to the rate of operationof said code following relay, an auxiliary relay having a contact whichalternates between two different positions when the auxiliary relay isenergized and which remains in the position to which last operated whenthe auxiliary relay is deenergized, means for tuning said circuit inaccordance with the position of said contact, means for energizing saidauxiliary relay including one transformer which is energized by energyof either frequency and another transformer which is energized only whenthe tuning of said circuit corresponds to the frequency of the energyflowing therein, said two transformers being connected in oppositionwhereby said auxiliary relay is energized only when the tuning of saidcircuit is out of correspondence with the frequency of the energyflowing therein, and a control relay receiving energy from said circuit.

10. In a coded signaling system, in combination, a signal, a codefollowing relay at times operating at one rate and at other timesoperating at another rate, a circuit having an inductive reactance and acapacity connected in series, said capacity including a plurality ofseparate sections which may be connected in multiple, said circuit beingtuned to pass energy at one frequency when all of said capacity isconnected in said circuit and being tuned to pass energy at anotherfrequency when a section of said capacity is disconnected from saidcircuit, a member oscillatable between a position in which it connectssaid capacity section in said circuit and a position in which saidcapacity section is disconnected from said circuit, means governed byflow of current in said circuit for oscillating said member and for alsocontrolling said signal, means for supplying current to said circuit atone or the other of said frequencies in accordance with the rate ofoperation of said code following relay, and means governed by the flowof current in said circuit and by the supply of current by said codefollowing relay for controlling said signal.

11. In a coded signaling system, in combine,- tion, a signal, a codefollowing relay at times operating at one rate and at other timesoperating at another rate, a circuit having an inductive reactance and acapacity connected in series, said capacity including a plurality ofseparate sections which may be connected in multiple, said circuit beingtuned to pass energy at one predetermined frequency when all of saidcapacity is connected in said circuit and being tuned to pass energy atanother predetermined frequency when a section of said capacity isdisconnected from said circuit, means governed by flow of current insaid circuit for alternately connecting said capacity section in saidcircuit and for disconnecting said capacity section from said circuitand for also controlling said signal, means for supplying current tosaid circuit at one or the other of said frequencies in accordance withthe rate of operation of said code following relay, and means governedby the flow of current in said circuit and by operation of said codefollowing relay for controlling said signal.

12. In a coded signaling system, in combination, a signal, a codefollowing relay at times operating at one rate and at other timesoperating at another rate, a circuit having inductive and capacityreactances connected in series therewith, one of said reactancesincluding a plurality of separate sections which may be connected inmultiple, said circuit being tuned to pass energy at one frequency whenall of said reactance sections are connected in said circuit and beingtunedto pass energy at another frequency when a section of saidreactance is disconnected from said circuit, means governed by the flowof current in said circuit for alternately connecting said reactancesection in said circuit and for disconnecting said reactance sectionfrom said circuit and for controlling said signal, means for supplyingcurrent to said circuit at one or the other of said frequencies inaccordance with the rate of operation of said code following relay, andmeans governed by flow of current in said circuit for also controllingsaid signal.

13. In a coded signaling system, in combination, a signal, a codefollowing relay at times operating at one rate and at other timesoperating at another rate, a circuit capable of being tuned to passenergy of one frequency or to pass energy of another frequency, a relayhaving a pair of windings and a movable member oscillatable betweenspaced positions by said windings, said member being operative in one ofits positions to tune said circuit to pass energy of one frequency andbeing operative in the other of its positions to tune the circuit topass energy of the other frequency, said member being moved to one ofits positions on energization of one of said windings, means associatedwith said member and operable only on movement of said member to saidone position to effect energization of the other of said windings, meansoperable on energization of the other of said windings to move themember to the other of its positions and to eifect the energization ofsaid first named winding, means responsive to the flow of current insaid circuit for governing energization of at least one of saidwindings, and a signal controlled by said relay in accordance withmovement of said movable member.

CRAWFORD E. STAPLES.

